Hmmm. This is an interesting move: Vodafone Australia has decided to move some of its data plans to a per minute charge instead of the traditional per kilobyte.

Let's go back a little. Until the introduction of packet data services (such as GPRS or CDMA 1xRTT), mobile data was charged on a per minute basis. That's because the data traffic was over a circuit switched connection (CSD). That is similar to a point-to-point connection between two modems.

On this situation, the switch had actually a pair of circuits in-use during the whole data call, and a voice call could not use these circuits on the switch. Hence the per minute charges.

With packet data, there's no circuit involved at the switch level, and the charges are based on actual data traffic. So if you use 100kb you pay more than if you use 10kb.

Vodafone Australia will now charge at AU$1/5 minutes. It means that if you use 4 minutes you pay AU$1, if you use 6 minutes you pay AU$10.

The operator says this is good: "Under our old pricing model $1 would buy you 50 Kilobytes (kb) of data. However, many games, videos and music clips available on the Mobile Internet are 100kb or more in size. Using our GPRS service, 100kb of data will download in about a minute (depending on network conditions).

During a 5 minute period, you could potentially download 2 or 3 items of this size meaning that $1 would buy you 300kb of data. This would cost you $6 under our old pricing model (@ 2c/kb) rather than $1 from 5 October 2005."

But what if the customer is on the wrong plan, and uses a Smartphone or PDA (such as Pocket PC or Treo)? Let's imagine there's a configuration problem and the connection is up because a program opens a connection, but it doesn't actually use any data.

It doesn't matter, the connection will still be charged.

Why is Vodafone Australia moving in this direction? Lack of IP addresses? I don't think so, their consumer network is behind a NAT proxy. Lack of circuits? It shouldn't be.

The company finishes with this push (no pun intended) of its Blackberry service:

"...if you are using your mobile device for Internet E-mail then you may need to modify your settings for how frequently your device connects to your e-mail server to check for incoming e-mails.

If you are connected to one of the plans listed above which will be impacted by the change from volume-based charging to time-based charging and not connected to a BlackBerry plan, then in most instances you will be charged $1 for each time your device checks your e-mail server, regardless of if you have received any e-mails.

If you use your device for Internet E-mail then you would normally be better of connecting to a BlackBerry plan. For more information on BlackBerry click here."